#ifndef XRPL_PROTOCOL_SEED_H_INCLUDED
#define XRPL_PROTOCOL_SEED_H_INCLUDED

#include <xrpl/basics/Slice.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/protocol/tokens.h>

#include <array>
#include <optional>

namespace ripple {

/** Seeds are used to generate deterministic secret keys. */
class Seed
{
private:
    std::array<uint8_t, 16> buf_;

public:
    using const_iterator = std::array<uint8_t, 16>::const_iterator;

    Seed() = delete;

    Seed(Seed const&) = default;
    Seed&
    operator=(Seed const&) = default;

    /** Destroy the seed.
        The buffer will first be securely erased.
    */
    ~Seed();

    /** Construct a seed */
    /** @{ */
    explicit Seed(Slice const& slice);
    explicit Seed(uint128 const& seed);
    /** @} */

    std::uint8_t const*
    data() const
    {
        return buf_.data();
    }

    std::size_t
    size() const
    {
        return buf_.size();
    }

    const_iterator
    begin() const noexcept
    {
        return buf_.begin();
    }

    const_iterator
    cbegin() const noexcept
    {
        return buf_.cbegin();
    }

    const_iterator
    end() const noexcept
    {
        return buf_.end();
    }

    const_iterator
    cend() const noexcept
    {
        return buf_.cend();
    }
};

//------------------------------------------------------------------------------

/** Create a seed using secure random numbers. */
Seed
randomSeed();

/** Generate a seed deterministically.

    The algorithm is specific to Ripple:

        The seed is calculated as the first 128 bits
        of the SHA512-Half of the string text excluding
        any terminating null.

    @note This will not attempt to determine the format of
          the string (e.g. hex or base58).
*/
Seed
generateSeed(std::string const& passPhrase);

/** Parse a Base58 encoded string into a seed */
template <>
std::optional<Seed>
parseBase58(std::string const& s);

/** Attempt to parse a string as a seed.

    @param str the string to parse
    @param rfc1751 true if we should attempt RFC1751 style parsing (deprecated)
 * */
std::optional<Seed>
parseGenericSeed(std::string const& str, bool rfc1751 = true);

/** Encode a Seed in RFC1751 format */
std::string
seedAs1751(Seed const& seed);

/** Format a seed as a Base58 string */
inline std::string
toBase58(Seed const& seed)
{
    return encodeBase58Token(TokenType::FamilySeed, seed.data(), seed.size());
}

}  // namespace ripple

#endif
